我有数据:
var data = [
{field1: 'a', field2: 'aa', field3: 1},
{field1: 'b', field2: 'bb', field3: 2},
{field1: 'c', field2: 'cc', field3: 3},
{field1: 'd', field2: 'dd', field3: 4},
]
我试图使用immutability-helper https://github.com/kolodny/immutability-helper或React {...data, }
构造得到以下结果:我需要找到field2
值'cc'
的行(一个或多个)并将其field3
设置为5
。我可以使用什么代码?
您可以使用纯JavaScript进行此操作:
data.map(d => d.field2 === 'cc' ? ({...d, field3: 5}) : d);
解释发生了什么:这将创建一个新数组,其中每个元素都是原始数组中元素的投影。如果它与条件匹配,则根据您的要求创建和修改对象的副本。如果它不匹配,则按原样放入数组中。
您可以在不可变的方法中使用Javascript的reduce
:
var data = [
{field1: 'a', field2: 'aa', field3: 1},
{field1: 'b', field2: 'bb', field3: 2},
{field1: 'c', field2: 'cc', field3: 3},
{field1: 'd', field2: 'dd', field3: 4},
]
var newData = data.reduce((accumulator, obj) => {
return accumulator.concat((obj.field2 === 'cc' ? {...obj, field3: 5} : obj));
}, []);
console.log(newData);
你可以使用简单的JavaScript函数Array.map
var data = [{field1: 'a', field2: 'aa', field3: 1},{field1: 'b', field2: 'bb', field3: 2},{field1: 'c', field2: 'cc', field3: 3},{field1: 'd', field2: 'dd', field3: 4}];
/* Using ...o to create a copy of object and updating the value in copied object. */
var result = data.map(o => Object.assign({...o}, {field3 : o.field2 === 'cc'? 5 : o.field3}));
console.log(result);